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    3rd header cold most of the time, but not always.

    I have an 82 gs650gl, that's I can't get to idle and seems to be having trouble getting the 3rd cyl to run. With full choke, it starts quickly, and most of the time clombs to about 200-2500 rpm and never moves past that, will die quickly if I let off the choke. Occasionally, I can get ti rev up to 7k or so, and then I can get it off the choke, but I have to stay on the throttle or it'll die. It seems like, on the occasions that I can get the RPM's up, that the 3rd cyl is running, otherwise, the header from #3 is cold (eventually it gets a little warm, but that's just conduction from the block, I'm pretty sure). 2 years ago, a pretty knowledgeable friend rebuilt the carbs and it ran fine the past two years, this year, when I pulled it out from storage, I have this problem with the #3 cyl. I've replaced the coils and the plug cables, swapped plugs, no avail. I pulled the drain plug for #3 and there was fuel in it. Anyone have any suggestions besides taking the carbs off and going through them again? Please?

    #2
    Originally posted by spadefoot View Post
    1982 GS650GL that's driving me to drink, but won't currently drive me to the store.
    Brilliant!!!! This is an issue I haven't had...yet, but others will be along with suggestions. Thinking perhaps compression or needing to rebore, but those are complete guesses. Do the plugs look clean when it runs?

    That it won't generally run when off choke sounds like fuel/air issue esp if you've swapped the electrical bits....

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      #3
      Originally posted by spadefoot View Post
      Anyone have any suggestions besides taking the carbs off and going through them again? Please?
      Ding, Ding, Ding, we have a winner!


      Life is too short to ride an L.

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        #4
        Well you have already figured this out. Your number 3 carb is not functioning properly. Pull, clean (24 hour soak in carb cleaner.....no shortcuts please)rebuild with new o-rings. Listen to Tkent, he knows whereof he speaks.

        What you are going through is nothing new and it happens to the best of us. It seems like a major undertaking but once you've done it a few times its easy.

        Good luck with it.

        cheers,
        Spyug

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          #5
          Hrm, well, if that's what I have to do, that's what I have to do. My friend that rebuilt them 2 years ago did use all new rings and so on, so I'm hoping a full rebuild of all 4 isn't necessary again.

          Given that I'm more cheap and stubborn than mechanically inclined: Is there a good step-by step to taking these apart, preferably with pictures? I'm really not very good at this kind of detail work, and terrified I'm going to end up with a box full of parts that I can't reassemble.

          I don't suppose there is anyone in the Eastern half of NC that works on these that anyone could recommend, is there?

          Thanks,

          Comment


            #6
            The GSR homepage has a link to a carb cleanup tutorial. cycleorings.com sells kits.

            Sounds like the choke pickup tubes are grunged up, and maybe the pilot jets too. Also, make sure the other maintenance is up to date (such as valve adjustment) and the stock airbox is in place and properly sealed. GS's don't run for crap with mods unless the carbs are appropriately jetted.
            Ed

            To measure is to know.

            Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

            Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

            Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

            KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

            Comment


              #7
              All the information given pointing to a carb cleaning is always spot on. Checking all clamps and boots, sealing of air box and everything else that needs to be tighten for air/fuel delivery matter needs to addressed. But, the point of a pilot jet and or passages restricted seems to be the direction to take. In my experiences with the way that gas seems to not last very long even with stabil in it. I would pull the rack and inspect (remove) #3 pilot jet and I bet you will find the tip of it plugged. It seems for ME that I just drain the tanks and fuel bowls for the winter.I used to stabil the tanks and drain the bowls. Not anymore. My bikes are stored inside in a controlled temp so this is the practice I use. Always the first matter of spring check over is removal of the rack and cleaning the pilot jets. Sounds crazy, but I always find that the tips maybe 1 will be restricted.. My tanks are spotless, I can only believe that it is created from the fuel. This is based only on my experiences and only my opinion. Bob

              Comment


                #8
                As Ed. says refer to the tutorial. It does seem a daunting task but trust me it is not. The hardest part is getting the carbs out of the bike and once you learn the technique even that is easy enough.

                To remove the carbs, remove the clamps to the stock airbox and the screws holding the airbox to the frame. Push the airbox back as far as you can. You may find it easier to get more room if you remove the battery and battery box as well.

                Once the airbox is back, loosen the clamps to the intake boots and grasping both sides of the carbs push down and wiggle back. they will pop free. Remove to the right side of the bike. Don't try and remove the cables with the carbs on wait until they are out. When putting them back in put the cables on first.

                Once the carbs are out you will want to clean off as much dirt as you can before you dissassemble. For this you can use mineral spirits, kerosene, pain thinner almost anything but gasolene (way too dangerous i.e. combustible and explosive). Get a shallow bucket or tub and a stiff bristle brush and or paint brush and clean off as much grime as you can.

                Once they are clean, you can dissassemble and clean as per the tutorial. Take your time and do a thorough job. Don't skip any steps. As we've mentioned, you need to dip them in carb cleaner and let them soak. Carb cleaner is reuseable and you can usually get it in gallon containers for around $20/25. What I do is use 4 plastic ice cream tubs and put one carb body in each then fill to cover with fluid. I also drop each jet and jet tube into the repective carb's container to soak. After 24/48 hours you can remove them. Have a look at the gunge that gets cleaned out. I find even 'clean" carbs leave a residue like small black pepper grounds.

                Once you are done with the cleaner put a funnel with a coffee filter in it into the container and strain the fluid. Its good for many more dips.

                If you take your time and do it right you will fix your problem.

                Good luck,
                Spyug

                Comment


                  #9
                  All of the above is good advice. However having a similar problem on mine (No2) & had the carbs off & apart 15 times, I did a compression test & got the following result: 1=10 bar 2=6 bar 3=9 bar 4=12 bar. You can now see that No2 cyl has a serious compression problem. So that's me next job!

                  Comment


                    #10
                    Originally posted by cockneyrick View Post
                    All of the above is good advice. However having a similar problem on mine (No2) & had the carbs off & apart 15 times, I did a compression test & got the following result: 1=10 bar 2=6 bar 3=9 bar 4=12 bar. You can now see that No2 cyl has a serious compression problem. So that's me next job!
                    Ride the hell out of it, once the carburetion is working correctly. Too rich will wear the rings, running correctly can fix it somewhat. A few thousand miles, anyway. The compression will probably come up some. How much? Don't know that one, sometimes they get as almost good as new.

                    You did adjust the valve clearances before the compression testing?


                    Life is too short to ride an L.

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                      #11
                      Nope, just needed to know if I should look beyond the carbs. Oh & mine's a 78 GS1000E

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                        #12
                        This is it

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                          #13
                          And again

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                            #14
                            Well, I have to rertract what I posted earlier. Had a similar problem today on my 82 850 today. Started it today, seemed sluggish on start-up ran kinda rough but straightened out to a normal Idle, I let it run and then I shut it down. Check the header pipes and #3 cyl. was cold... Right away Made sure that the cyl. was firing with a spare plug resting on the head. Then went into carb removal mode. Fortunately, removal is 15 minutes. Opened #3 fuel bowl and removed the jet. Clean, and I was surprised. Put It all back together and fired it up. #3 still cold. I pulled the plug and checked for spark nothing. Tried a spare plug and it had spark. These plugs are relatively new. So, the moral for myself is never assume and be more thorough on preliminary trouble shooting. Bob

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                              #15
                              Originally posted by cockneyrick View Post
                              All of the above is good advice. However having a similar problem on mine (No2) & had the carbs off & apart 15 times, I did a compression test & got the following result: 1=10 bar 2=6 bar 3=9 bar 4=12 bar. You can now see that No2 cyl has a serious compression problem. So that's me next job!
                              By the look of your bike, I'm assuming you've kept the valves adjusted (?)

                              What carbs are you running on it?
                              1978 GS 1000 (since new)
                              1979 GS 1000 (The Fridge, superbike replica project)
                              1978 GS 1000 (parts)
                              1981 GS 850 (anyone want a project?)
                              1981 GPZ 550 (backroad screamer)
                              1970 450 Mk IIID (THUMP!)
                              2007 DRz 400S
                              1999 ATK 490ES
                              1994 DR 350SES

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